Edit: Naturally this only works with ANDROID, if you have iphone, too bad....I'll still leave the instructions here in case any other people want to know how to do this.
I just got it working in tasker, it's a little tiny bit complicated but it works and it's easy to set up.
Ok so first, download tasker (it's worth the price)
open tasker and create a new profile with the context being Event > Phone > Missed Call. Leave caller blank as you want this to work on all calls I assume. The way to get back and "save" your progress is to hit the arrow at the top left, directly to the left of the cog wheel icon. Otherwise you may lose your progress.
Once you hit the cog wheel icon, it will ask you to set up a task. Click new task. Name it whatever, doesn't matter.
First we want to set your alarm to max volume. To do this Hit the plus sign at the bottom, then go to Audio > Alarm Volume. Set it to as high as it will go (7 on mine) and hit the cog wheel back button at the top left.
Now click the plus sign at the bottom of the phone and go to Media > Music Play.
Select the file you want it to play (any sound will do as long as it's loud and you know it'll wake you up). You may have to download a sound file from somewhere if you don't have any available to you. Since I have google hangouts installed, it has a ringtone in there that I could use.
Set stream to ALARM, then hit the cog wheel thing at the top left again to go back.
Finally we will add a menu item that will allow you to turn off the alarm once you have woken up. Click the plus sign at the bottom of the phone once more, then click Alert > Menu. Title it whatever you want, then at the bottom hit the plus sign in the Items area. Make the label whatever you want ("I'm Awake" works) and click Action. Click Media > Music Stop. Hit the cog wheel back button thing again. Add an icon if you want to the left of the label, not required. Once you're done hit the cog wheel back button, and your tasker should look like this:
If it does, hit the cog wheel back button again and you're done! Restart tasker (disable tasker by holding down the cog wheel at the top left till it goes gray, then hold it again till it goes to color) and test it out by calling yourself and hanging up. You can also test it by simply hitting that little play button at the bottom left but I prefer a "real world" test to make sure it will actually work outside of the app's sandbox.
Tasker is pretty awesome for things like this. I have another profile set to when I plug in my headphones the phone unlocks and pandora automatically starts and turns the vol up to the level that I prefer and sets the screen timeout to 2 hours (I use this when I plug my phone into the car aux port). When I unplug the headphones it closes pandora and locks the phone.
I have another one that sends a text to my fiance when I am at a certain intersection so that she knows when to start packing up so she can hop in the car as soon as I get to her work (we only have one car at the moment). It texts her again when I arrive at her location.
I just started using tasker not long ago and I love it already, I'm constantly trying to set up cool things to do with it.